This week, the planet Venus will be at its brightest. The Cloud Planet will reach its greatest illuminated extent on Friday, December 6, showing us more of its face than at any other time in its orbit.
Venus, whose orbit lies a mere 26 million miles from our own, is our closest neighbor, and is usually the brightest object in the night sky, after the Moon. Every once in a while, if Venus is particularly far from us in its orbit, Mars, our next nearest neighbor, shines a little brighter.
The planet is most often known as either the Morning Star or the Evening Star, because it always stays close to the Sun. Depending on where it is in its orbit — either trailing the Sun or leading it — it usually comes out right before sunrise or just after sunset. Because it is brighter than all of the stars, it can be seen at dusk, before the other stars come out, or dawn, after they’ve faded away.
While we typically see Venus as a dot in the sky, the planet actually has phases, similar to our Moon. Though it will look exceptionally bright throughout this month, if you were to view it through a telescope, you’d only be able to see a small portion of the planet’s illuminated face. Because Venus’ orbit is inside of ours, we can only ever see its bright side, which reflects the light of the Sun, from an angle.
On December 6, when the planet reaches its greatest illuminated extent, we’ll be able to see slightly more than a quarter of the planet’s disk illuminated by the Sun — comparable to a thin crescent Moon.
It’s kind of amazing to realize that what we can see of the brightest body in our night sky represents only a fraction of its true radiance.
Because our orbit and Venus’ don’t line up perfectly, we only get to see Venus this bright once every eight years. The next time won’t be until the year 2021.
Enjoy this month’s great views of Venus while they last. The Evening Star will leave the night sky on January 1, 2014, and stay hidden from view until January 20, when it will reappear as the Morning Star.